Seismic activity at Shishaldin Volcano is back down after an eruption yesterday caused flights to be cancelled out of Cold Bay – about 58 miles to the northeast.
The Alaska Volcano Observatory (AVO) lowered the Aviation Color Code to "orange" and Alert Level to "watch."
The volcano has been active since July, and has had two ash eruptions in the past week.
On Friday, a low-level eruption produced an ash cloud approximately 24,000 feet accompanied by volcanic lightning. Yesterday, the volcano began erupting early in the morning and sent an ash cloud 27,000 feet that disrupted aviation and caused some ash fall in nearby Cold Bay, causing the alert level to increase.
Hans Schwaiger, a geophysicist with the AVO, said ash emissions have declined significantly since yesterday afternoon, and seismic activity at Shishaldin is low.
"Shishaldin has been one of the volcanoes that has been active over the last many decades," said Schwaiger. "In the late 1990s there was an eruption that sent a plume quite high, and then it was quieter for a while. But every few years it seems like it's becoming a bit active. So we're in the middle of an eruptive sequence right now, and so it will likely continue for a bit. We don't know for how long, but this isn't anything outside of its normal behavior."
The AVO is monitoring the volcano closely, and while there are no indications of a major eruption, Shishaldin is a volcano with an ability to ramp up quickly. It has had at least 54 episodes of unrest, including over 24 confirmed eruptions, since 1775.
The AVO said satellite data suggests continued low-level eruptive activity. It is possible for more explosive activity to resume with little warning.